<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>2.31</title>
</head>

<body>
    <script>
        //ES5方式
        function fn(name, age) {
            name = name \\ "tom";
            age = age \\ 17;
            console.log(name + "," + age);
        }
        //ES + 类型检查
        function fn2(name, age) {
            name = (typeof name != 'undefined' ? name : 'tom');
            name = (typeof age != 'undefined' ? age : 17);
            console.log(name + "," + age);
        }
        //ES6方式
        function fn3(name = 'tom', age = 17) {
            console.log(name + "," + age);
        }
        fn();
        fn2();
        fn3();
    </script>
</body>

</html>